FMVSS 302: Flammability Testing for Vehicle Interior Materials

What is FMVSS 302?

FMVSS stands for Federal Motor Vehicle Safety Standard, and number 302 is specifically about flammability of interior materials. The rule limits how quickly a material can burn when exposed to a small flame.

The benchmark is clear: the burn rate must not exceed 102 millimeters per minute (about four inches per minute). By setting this cap, the regulation ensures that materials inside the vehicle give passengers enough time to escape if a fire starts.

The scope of FMVSS 302 covers items such as seat cushions, seat backs, headliners, carpets, sun visors, and even seat belt webbing. Essentially, anything inside the passenger compartment that could catch fire has to meet the requirement.

How the FMVSS 302 test works

The test is relatively simple, which is one reason it has endured:

FMVSS 302 Test Steps

1. Sample preparation: A strip of material is cut, usually 356 mm long and 100 mm wide.

2. Positioning: The strip is placed horizontally inside a controlled test chamber.

3. Ignition: A small flame is applied to one end of the strip for 15 seconds.

4. Observation: If the flame goes out before traveling 38 mm, the material automatically passes.

5. Calculation: If the flame continues, the burn rate is measured. To pass, it must be at or below 102 mm per minute.

It is a straightforward method, but it provides a consistent way to compare materials.

Where the standard applies

FMVSS 302 was written for the automotive industry in the United States, yet its influence is global. Many suppliers and manufacturers outside the US still test to this standard because it is widely recognized and relatively easy to demonstrate.

• In civilian vehicles, materials like upholstery and floor mats must comply. Even though modern cars have advanced safety systems, this regulation ensures the interior does not become fuel for fire.

• In industrial vehicles such as forklifts, construction machines, and mining equipment, compliance provides peace of mind in environments where fire risks are high and evacuation routes are limited.

• In military applications, FMVSS 302 often serves as a baseline before stricter military standards are applied. A troop carrier or armored vehicle may face combat fire risks, but the materials inside still need to resist ordinary flame spread.

FMVSS 302 compared with other flammability standards

To put FMVSS 302 in context, here is a quick comparison with related standards:

If you are supplying across regions, you may be asked for multiple test reports. Fortunately, passing FMVSS 302 often helps with compliance under these related standards.

Points of interpretation

Although the test is simple, applying it in practice can be complicated. A few common issues include:

• Thickness variation: a material may pass at one thickness but fail at another.

• Layered assemblies: adhesives, coatings, or laminates may alter burn behavior.

• Aftermarket parts: replacement covers or trims may not meet the same standard as original equipment.

For procurement and safety officers, this means that simply seeing “FMVSS 302 compliant” is not enough. Always ask whether the test was done on the raw material, the finished part, or the complete assembly.

Relevance in the age of electric and hybrid vehicles

With the rise of electric and hybrid vehicles, fire safety has taken on new dimensions. Battery-related incidents may be very different from a burning seat cushion, yet interior materials still matter. If a battery fire spreads into the cabin, the time passengers have to escape can depend directly on whether the materials meet FMVSS 302.

Military planners face similar concerns with next-generation hybrid and electric armored vehicles. The principle is the same: slowing fire spread inside a confined space buys critical seconds for survival.